"This is like a high school reunion, but much worse because they all still look really great," Whedon says.

He and series stars including David Boreanaz, Nicolas Brendon, Charisma Carpenter and Michelle Trachtenberg share memories of their days on the show and reflect on its enduring impact.

Buffy the Vampire Slayer premiered in 1997 and ran through 2003. Its title character battled vampires, demons and other dark forces while navigating everyday teenage struggles. Whedon was nominated for an Emmy for his writing on the show in 2000.

The show was "the ultimate metaphor," Gellar says.

"It was utilising the horrors of adolescence manifested through these actual monsters," she says. "And I think that (for) everyone going through it, that's the hardest time of life and to understand that you're not alone through that."

The interview was filmed earlier this month in Los Angeles. The reunited "Buffy" cast also appears on the cover of the upcoming issue of Entertainment Weekly magazine, available Friday.